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1.
A study was undertaken to investigate the effects of graded dietary levels and different types of carnitine on hybrid striped bass (Morone chrysops × M. saxatilis %) fed different levels of lipid. An incomplete factorial design was utilized in which diets containing lipid at either 5 or 10% were supplemented with l-carnitine at 0, 500, or 1000 mg kg–1 diet, dl-carnitine at 1000 mg kg–1 diet, or carnitine chloride to provide 1000 mg carnitine kg–1 diet. Juvenile hybrid striped bass (3.3 g fish–1) were stocked into individual 38-l aquaria connected as a brackish water (6), recirculating system and fed each diet in triplicate for 9 weeks.Supplementation of the diet with 1000 mg carnitine kg–1 increased muscle carnitine from 35.5 to 47.7 g g–1 tissue. Carnitine supplementation did not result in increased weight gain regardless of carnitine level or type; however, weight gain showed a significant (p<0.05) response to dietary lipid with fish fed diets containing 10% lipid growing 34% more than fish fed diets with 5% lipid. The hepatosomatic index also was unaffected by diet, but the intraperitoneal fat (IPF) ratio was significantly elevated (5.1 vs 3.2%) in fish fed diets with 10% lipid compared to those fed diets with 5% lipid. Fish fed diets containing 1000 mg carnitine kg–1 had increased IPF ratio values at 4.7% compared to 3.9% for fish fed the basal diet. Liver lipid also was responsive to dietary treatment, increasing from 6.7 to 8.8% of wet weight as dietary lipid increased from 5 to 10%. The relative quantities of triglycerides, free fatty acids and phospholipids in muscle and liver were not influenced by carnitine level, carnitine type or dietary lipid level. Supplementation of carnitine does not appear to be beneficial to hybrid striped bass based on either growth performance or body composition.  相似文献   

2.
The nutritional effect of vitamin E in dietsfor Litopenaeus vannamei postlarve (PL19)was investigated. Four formulated diets withdifferent combinations of -tocopherylacetate (-TA), ascorbic acid (AA) andhighly unsaturated fatty acids (HUFA) weretested, using four replicates.No significant differences in survival wereobserved among treatments after 34 days offeeding. However, shrimp fed with a dietcontaining 2% fish oil (low n-3 HUFA content),200 mg.kg–1 -TA and100 mg.kg–1 AA (diet H/E/C) showedsignificantly better growth than those fed adiet supplemented with 5% fish oil (high n-3HUFA content), 200 mg.kg–1 -TA and100 mg.kg–1 AA (diet H+/E/C). Shrimp fedwith a diet containing 5% fish oil,900 mg.kg–1 -TA and100 mg.kg–1 AA (diet H+/E+/C) showed a significantly higher tissue level of n-6 PUFAthan postlarvae fed diet H+/E/C. No definiteconclusion could be drawn about a possibleinteraction between -TA and AA, since acomparison of the diet containing 5% fish oil,200 mg.kg–1 -TA and700 mg.kg–1 AA (H+/E+/C+) and the dietH+/E/C did not show any significant differencesin any of the measured parameters. Theantioxidative status of the shrimp tissue(measured by means of the thiobarbituric acid(TBA) assay and expressed as nM malonaldehyde(MA) per gramme dry weight) was equal for alltreatments. Nevertheless, there was a slightlylower MA value with the diet H+/E/C+,indicating that AA may be an effectiveantioxidant in the aqueous phase and at thewater/lipid interface of the tissue. The tissuelevels of -T and AA were highlydependent on the amounts in diets and nocorrelation between -T and AAincorporation could be observed.  相似文献   

3.
Asian catfish, Clarias batrachus, were fed semi-purified basaldiets containing 0, 0.1, 0.5, 1, 3 and 5 mg biotin kg–1diet for 60 days. Fish fed the control diet (no biotin) showed(P < 0.05) higher mortality, lower weight gain, specificgrowth rate (SGR), feed efficiency ratio (FER) and protein efficiencyratio (PER) than in fish fed diets supplemented with biotin. The highestweight gain, SGR, FER and PER were noticed in fish fed 1 mg biotinkg–1, followed by 0.5, 5, 3 and 0.1 mg biotinkg–1, except for PER (followed by 0.5, 5, 0.1 and 3 mgbiotin kg–1). Quadratic analysis showed that the optimumdietary biotin requirements for maximal weight gain, PER and PER were2.49, 2.54 and 2.52 mg kg–1, respectively. Liver biotinconcentrations were influenced by levels of biotin in the diet.Concentration of liver biotin increased as level of dietarysupplementation increased and no biotin was detected in the liver of thecontrol fish. Liver pyruvate carboxylase and acetyl CoA carboxylaseactivities were higher in fish fed biotin-supplemented diets than incontrols. Biotin concentrations, pyruvate carboxylase and acetyl CoAcarboxylase activities in liver associated with normal growth rangedfrom 10.59 to 10.66 g g–1, 147.97 to 148.18 units mgprotein–1 and 12.76 to 12.78 units mg protein–1, respectively. Biotin deficiency symptoms such as anorexia, darkskin colour and convulsions were observed in fish fed the control diet.The optimum dietary biotin requirement for maximal growth of C.batrachus is about 2.49 mg kg–1 diet.  相似文献   

4.
High zinc diet of 2000 mg kg–1 was fed to common carp (Cyprinus carpio), grass carp (Ctenopharyngodon idellus) and tilapia (Oreochromis aureus) for 8 weeks to compare the accumulation of Zn in fish. It was found that accumulation of zinc from diet by grass carp and tilapia was low when compared to common carp. The largest difference occurred in digestive tract tissue. The digestive tract tissue of common carp had a large pool of stored zinc, the mean storable capacity is about 1500 g Zn g–1 fresh tissue, and the time needed to saturate the tissue when feeding 2000 mg Zn kg–1 diet is about 8 weeks. The accumulated Zn in the digestive tract tissue of common carp was released when the dietary Zn was reduced to normal level (50 mg kg–1) or deficient level (4 mg kg–1) for 4 weeks.Subcellular fractionation results indicate that Zn accumulated in digestive tract tissue of common carp was accumulated mainly in the nuclei/cell debris fraction. Exposure to a high Zn diet induced some metallothionein-like substance in the digestive tract tissue and the hepatopancreas of common carp, but the amount was very low when compared with the amount of Zn accumulated in the nuclei/cell debris fraction.  相似文献   

5.
Rainbow trout (Oncorhynchus mykiss) with a mean (sd) weight of 120 (2) g were fed diets supplemented with astaxanthin extracted from the yeast Phaffia rhodozyma (OY1 = 50 mg carotenoids kg–1 feed, OY2 = 100 mg carotenoids kg–1 feed), astaxanthin (AX = 100 mg astaxanthin kg–1 feed) and canthaxanthin (CX = 100 mg canthaxanthin kg–1 feed) for 4 weeks. Muscle analyses at the end of the experiment indicated a significantly higher carotenoid concentration in the AX group, while CX and OY1 groups were similar in spite of the differences in dietary concentration. The measure of total muscle colour difference (E* ab) between initial samples and 4 week ones was higher for the AX fish group but showed no significant difference between OY1, OY2, and CX. The hue and the reflectance ratio (R650:R510) of fish muscle increased in proportion to carotenoid intake. Digestibility (ADC) of yeast astaxanthin in OY1 and OY2 groups was significantly higher than that in the AX group. Canthaxanthin ADC was about one sixth of that of astaxanthin (AX group). Carotenoid retention in the muscle, expressed as a percentage of carotenoid intake, was higher for the AX group than that recorded for OY1 and OY2. According to ADC, carotenoid retention showed a marked lower value for the CX group. Muscle retentions were similar for astaxanthins from both sources.  相似文献   

6.
The impact of feeding, fish size (body weight from 18.5 to 56.5 g) and water temperature (20 and 23 °C) on oxygen consumption (OC, mg O2 kg–1 h–1) and ammonia excretion (AE, mg TAN kg–1 h–1) was studied in Eurasian perch held in recirculation systems. OC for both fed and feed-deprived (3 days) fish was higher at 23 °C (278.5 and 150.1 mg O2 kg–1 h–1) than at 20 °C (249.3 and 135.0 mg O2 kg–1 h–1; P < 0.01). AEs for both fed and feed-deprived fish were also significantly higher at 23 °C than at 20 °C (P < 0.001). Water temperature and fish size had a significant impact on the oxygen:feed ratio (OFR, kg O2 kg–1 feed fed day–1) and ammonia:feed ratio (AFR, kg TAN kg–1 feed fed day–1; P < 0.001). Their average values at temperatures of 20 and 23 °C were 0.17 and 0.19 kg O2 kg–1 feed fed day–1 and 0.009 and 0.011 kg TAN kg–1 feed fed day–1, respectively.  相似文献   

7.
Lipid peroxidation, protein oxidation and antioxidant activities of muscle, intestine, hepatopancreas and serum in juvenile Jian carp (Cyprinus carpio var. Jian) were investigated after feeding graded levels of biotin (0.010, 0.028, 0.054, 0.151, 0.330, 1.540 and 2.680 mg kg?1 diet) for 63 days. Both malondialdehyde and protein carbonyl content in all studied tissues and serum were the lowest in fish fed diets containing 0.151–0.330 mg biotin kg?1 diet and then increased in fish fed the diet with 2.680 mg biotin kg?1 diet (P < 0.05). Similarly, glutamate–oxaloacetate transaminase and glutamate–pyruvate transaminase activities in serum significantly decreased with biotin levels up to 0.151 mg kg?1 diet (P < 0.05). Conversely, capacities of anti-hydroxyl radical (AHR) and anti-superoxide anion (ASA) in the detected tissues and serum significantly improved with biotin levels up to 0.054–1.540 mg kg?1 diet and then decreased in 2.680 mg biotin kg?1 diet group for muscle and intestinal AHR as well as hepatopancreas ASA (P < 0.05). Activities of superoxide dismutase in all studied tissues and serum significantly elevated with biotin levels up to 0.330 mg kg?1 diet and then decreased when fish fed the diet with 2.680 mg biotin kg?1 diet, except intestine (P < 0.05). Meanwhile, activities of catalase, glutathione peroxidase, glutathione-S-transferase and glutathione reductase and total thiol content in all studied tissues and serum showed the upward trend with biotin supplementations (P < 0.05). These results indicated that biotin improved antioxidant status and depressed lipid peroxidation and protein oxidation in all studied tissues and serum.  相似文献   

8.
In this investigation, the efficacy of a single intraperitonealinjection of either flumequine or oxytetracycline hydrochloride to preventoutbreak of atypical Aeromonas salmonicida infection ingoldsinny wrasse, Ctenolabrus rupestris, following stresswas studied. Six groups of goldsinny wrasse, each of 50 individuals, weretreated with an intraperitoneal injection of either propylene glycol : saline(50 : 50), 200 mg kg–1 of oxytetracycline or 50mg kg–1 of flumequine dissolved in propyleneglycol : saline (50 : 50). Three days following medication the fish in allgroups were stressed by an intraperitoneal injection of prednisolone acetate(0.05 ml) and a rise in seawater temperature from 9 to 11°C. Mortality was observed daily for 21 days. Flumequine wasthe more effective with a mean cumulative mortality of 5% compared tooxytetracycline with 54%. The mean cumulative mortality in the unmedicatedcontrol groups was 84%. Bacterial examination of kidneys from dead fishconfirmed the presence of atypical A. salmonicida as theprobable cause of death. Minimum inhibitory concentration (MIC) values forflumequine and oxytetracycline against the isolated A.salmonicida were determined to 0.13 gml–1, and 2.0 g ml–1,respectively.  相似文献   

9.
This study was conducted to study the effects of dietary zinc on lipid peroxidation, protein oxidation and antioxidant defence of juvenile Jian carp (Cyprinus carpio var. Jian) by feeding fish with increasing levels of zinc (15.3, 26.9, 40.8, 58.2, 68.9 and 92.5 mg Zn kg?1) for 6 weeks. Results indicated that malondialdehyde (MDA) content and protein carbonyls (PC) in serum were the highest in fish fed diet containing 15.3 mg zinc kg?1 diet (P < 0.05). Serum antisuperoxide anion (ASA), superoxide dismutase (SOD), glutathione peroxidase (GSH‐Px), glutathione reductase (GR) activities and glutathione (GSH) content were improved with increasing dietary zinc levels up to 40.8 mg zinc kg?1 diet (P < 0.05) and levelled off (P > 0.05). Serum antihydroxy radical (AHR), catalase (CAT) and glutathione‐S‐transferase (GST) activities followed the similar pattern to that observed in ASA. The MDA and PC levels, ASA, AHR, SOD, CAT, GPx, GR, GST activities and GSH content in intestine, hepatosomatic and muscle tissue followed the similar pattern to that observed in serum. The present results indicated that zinc decreased lipid peroxidation and protein oxidation and improved antioxidant defence in fish.  相似文献   

10.
Drinking in freshwater juvenile salmon was investigated in response to vasodilation by sodium nitroprusside (SNP), a nitric oxide donor, which significantly increased blood vessel diameter in Atlantic salmon alevins. Atlantic salmon fry (1–3 g), as previously shown, drank at a significant rate in fresh water which doubled to about 1.2 ml kg–1 h–1 following injection of SNP (100 mol kg–1), through dilation of body vasculature and activation of a vasoconstrictive mechanism, the endogenous renin angiotensin system (RAS). This response was 50% inhibited by injection of about 100 mg kg–1 enalapril. Fry increased drinking in response to SNP administered in the water, though the concentration required for maximal response, 1.6 mmol l–1, was much greater than for injected SNP; this response was also inhibited by enalapril injection. Possible involvement of the gill vasculature and branchial osmoreceptors or baroreceptors in control of the drinking response is discussed.  相似文献   

11.
Doppler flow probes were fitted around the ventral aorta of rainbow trout, which were exposed to combinations of pH and aluminum (pH 5.1–6.2, Al 0–80 g l–1) for 60 h. Fish accumulated Al at the gill and exhibited decreased blood Na+, Cl–, and Ca2+ concentrations, and increased K+, hematocrit, hemoglobin, glucose, and lactate, indicating increasing ionoregulatory disturbance with increasing Al concentration. Fish exposed to ambient water (6.2) or low-pH (5.3) water without Al exhibited slight reductions in heart rates, as well as increased stroke volume, resulting in little variation in cardiac output. In the presence of Al (20 to 40 g l–1) at low pH (5.1–5.3), fish increased their heart rate slightly and generally maintained their stroke volume, resulting in increased cardiac output in the first two days of exposure. At the highest Al concentration (80 g l–1, pH 5.1), tachycardia was observed, concomitant with a decrease in stroke volume. The ionoregulatory imbalance and resulting increased blood viscosity explain these increases in heart rate rather than stroke volume in fish exposed to high concentrations of Al.  相似文献   

12.
This study was conducted to evaluate the effects of different concentrations of dietary lipids on body composition and liver function in juvenile red drum, Sciaenops ocellatus. Diets were formulated to contain 40% crude protein from solvent-extracted menhaden fish meal and 0, 7, 14 or 21% lipid from menhaden fish oil. The basal diet, without supplemental fish oil, contained lipid at 0.4% of dry weight. The diets were fed to groups of 25 juvenile red drum initially averaging 7.3 ± 0.18 g fish–1 in a recirculating culture system for 8 weeks and weight gain was recorded. After an additional 8 weeks, 16 fish from each treatment were sacrificed and the following measurements were recorded: hepatosomatic index (HSI), intraperitoneal fat (IPF) ratio, and liver -tocopherol, malondialdehyde (MDA) formation, and cytochrome P-4501A activity (measured as 7-ethoxyresorufin O-deethylase (EROD) activity). The activity of alanine and aspartate aminotransferases and concentrations of -tocopherol also were measured in plasma.Weight gain was significantly (p<0.05) affected by dietary lipid concentration, with values ranging from 361% of initial weight for fish fed the basal diet to 527% of initial weight for fish fed the diet containing 7% lipid. The HSI and IPF ratio values also were significantly affected by lipid with the lowest values recorded for fish fed the basal diet and the highest values observed in fish fed the diet containing 21% lipid. Increasing dietary lipid significantly increased oxidative stress as reflected in reduced -tocopherol in liver and plasma and increased MDA formation in the liver, although no overt pathological signs were observed. These findings suggest that lipid concentrations between 7 and 14%, when the diet contains 60 IU vitamin E kg–1, are likely to limit oxidative stress and result in normal physiological responses of red drum.  相似文献   

13.
Total lipids, lipid classes and their associated fatty acids were measured in developing eggs, yolksac larvae and starving larvae (from fertilized egg to day 9 after hatch) of the common dentex Dentex dentex (L., 1758). The larvae of common dentex during lecitotrophia and subsequent starvation consumed 1.6 g of total lipid per larvae per day. The overall decrease was mainly due to utilization of the major neutral lipids, TAG and SE (0.5 and 0.6 g larvae–1 day–1, respectively) which was 3.4-fold greater than that of the the major phosphoglycerides (primarily PC by 0.2 g larvae–1 day–1). There was net synthesis/conservation of PE during the first half of the study period before it decreased rapidly (0.2 g larvae–1 day–1) during the second half. PUFAs were principally catabolized (468.6 ng larvae–1 day–1), primarily 22:6(n-3), 20:5(n-3) and 20:4(n-6) (221.8, 58.5 and 12.1 ng larvae–1 day–1, respectively). Saturated and monounsaturated fatty acids were also utilized (227.2 and 256.7 ng larvae–1 day–1, respectively), principally 16:0 and 18:1(n-9) that were both consumed at 149.8 and 156.7 ng larvae–1 day–1, respectively. The rank order of utilization of fatty acids (ng larvae–1 day–1) by D. dentex larvae from total lipids, PC and TAG coincided with the order of abundance of the different fatty acids in the respective lipid fractions. However, in PE, the most abundant fatty acid, DHA, was relatively conserved and 16:0, the second most abundant fatty acid, was catabolized to the greatest extent. D. dentex showed a pattern of lipid metabolism during early development similar to that of marine larval fish from temperate waters whose eggs contain high levels of total lipids, including an oil globule, and which preferentially utilize neutral lipids as the primary energy source.  相似文献   

14.
Protein synthesis was assessed in rainbow trout (Oncorhynchus mykiss) hearts perfused with medium containing 3H phenylalanine. Isolated hearts from fish acclimated to 5° and 15°C were used as the model system, and were perfused at variable test temperatures and pH. Protein synthesis expressed as nmol PHE mg protein–1 h–1 was two fold higher in hearts from fish acclimated to 15°C and tested at 15°C and extracellular pH 7.6 than in hearts from fish acclimated to 5°C and tested at 5°C and extracellular pH 8.0. The prime determinant of the decreased rate of protein synthesis was thermal history. Fish acclimated to 5°C had lower levels of RNA mg protein–1 than fish held at 15°C. There was a direct linear relationship between the rate of protein synthesis in nmol PHE mg protein–1 h–1 and RNA content. RNA activity (nmol PHE g RNA–1 h–1 remained constant regardless of thermal history or perfusion condition. Elevated pH resulted in only a marginal decrease in protein synthesis. Test temperature had no effect on in vitro rates of protein synthesis.  相似文献   

15.
Soft water acclimated (Ca2+ 0.02 mM; Na+ 0.03 mM; K+ 0.01 mM; pH 7.0), cannulated brown trout (Salmo trutta) were exposed to various pH and aluminium (Al) regimes (pH 7.0, pH 5.0, pH 5.0 plus Al: 50, 25, and 12.5 g l–1) for up to 5 days in order to determine (i) the sublethal concentration of Al at pH 5.0 for this species (ii) their ionoregulatory and respiratory status. No mortality or physiological disturbances were evident at pH 7.0 or pH 5.0. All trout died within 48 h at pH 5.0 in the presence of Al at 50 g l–1 and 67% died over the 5 day period at pH 5.0 in the presence of Al at 25 g l–1. Fish at these lethal Al concentrations showed significant decreases in arterial blood oxygen content (CaO2) but no changes in plasma osmolarity or the concentrations of plasma Na+, K+ and Cl–. Physiological disturbance was more marked at the 50 g l–1 Al concentration. The surviving fish at 25 g l–1 showed few signs of physiological recovery while continually exposed to this regime. No fish died during the exposure to water of pH 5.0 containing 12.5 g l–1 Al, but physiological disturbance was still apparent. These sublethally-stressed trout showed a transient decline in the plasma concentrations of Na+ and Cl–1. Although CaO2 decreased, recovery was evident. The data suggest that in the brown trout, environmental Al concentration is as important as pH and calcium concentration in determining the physiological status of the fish.  相似文献   

16.
This study aimed to evaluate the protein-sparing effect of dietary lipid on digestive and metabolic responses of fingerling Megalobrama amblycephala. Fish were fed nine practical diets with three protein levels (270, 310 and 350 g kg−1) and three lipid levels (40, 70 and 100 g kg−1) for 8 weeks. Weight gain was significantly affected only by dietary lipid levels with the highest found in fish fed 70 g kg−1 lipid. Relative feed intake and whole-body protein content showed little difference among all the treatments. Activities of intestine lipase and amylase increased significantly as dietary lipid levels increased, whereas little difference was observed in protease activities. Liver lipid content was significantly affected only by protein levels with the lowest found in fish fed 310 g kg−1 protein. Liver aspartate aminotransferase (GOT) activities increased significantly with decreasing lipid levels, whereas the highest GOT activity was obtained in fish fed 310 g kg−1 protein in terms of dietary protein levels. Activities of liver lipoprotein lipase, total lipase and plasma cholesterol concentration of fish fed 350 g kg−1 protein were significantly lower than that of the other groups, whereas the same was true for plasma 3, 5, 3′-triiodothyronine level of fish fed 270 g kg−1 protein. The results indicated that an increase of dietary lipid content from 40 to 70 g kg−1 can enhance the growth and digestive enzyme activities of this species and reduce the proportion of dietary protein catabolized for energy without inducing hepatic steatosis; meanwhile, decreasing protein level from 350 to 310 g kg−1 leads to the increase of lipase activities both in intestine and liver coupled with the reduced liver lipid content.  相似文献   

17.
Atlantic salmon (Salmo salar L) postsmolts weighing 150 ± 53 g were exposed to 14–15 mg l–1 TA-N (total ammonia-N) in sea water in 1 m3 tanks for 24h. Blood samples were then taken A) immediately after the fish were netted from the exposure tanks and stunned by a blow to the head; B) 2–20 min after the fish were transferred to 15 l of an anaesthetic solution of metomidate in ammonia-free sea water; or C) 2–20 min after the fish were transferred to 15 l of ammonia-free sea water. Plasma TA-N level was 18% lower in the anaesthetised fish compared to in the fish sampled directly from the exposure tanks (p 0.05), and accordingly 16% lower in the fish transferred to pure sea water although this difference was not significant (p = 0.07). Plasma glucose level was higher in the fish transferred to pure sea water than in the fish receiving the two other treatments (p 0.05), but plasma urea, osmolality, Na+, Cl–, Ca2+ or Mg2+ levels did not vary significantly between the different treatments. Plasma TA-N level increased with time in the fish in the metomidate solution (p 0.02).  相似文献   

18.
This paper compares and discusses the accumulation of eight heavy metals (Cd, Co, Cr, Cu, Pb, Fe, Mn and Zn) and total phosphorus (TP) in surface sediments from five intensive farms of tilapia Oreochromis niloticus×Oreochromis aureu, Asian seabass Lates calcarifer and white shrimp Litopenaeus vannamei (n=75). Results indicate that the sediments were significantly contaminated by Cd, Co, Cr, Cu, Pb, Fe, Mn and Zn as well as P. The mean concentrations of Cd (0.47 mg kg?1), Co (2.25 mg kg?1), Cu (31.56 mg kg?1), Pb (23.45 mg kg?1), Fe (1.15%), Mn (145.5 mg kg?1), Zn (41.5 mg kg?1) and TP (750.69 mg kg?1) in tilapia farm surface sediments were significantly lower than the levels observed in Asian seabass and white shrimp farm surface sediments, where the concentrations were, respectively, Cd – 2.69 and 2.35 mg kg?1, Co – 17.66 and 15.22 mg kg?1, Cu – 116.84 and 110.03 mg kg?1, Pb – 38.5 and 33.26 mg kg?1, Fe – 3.4% and 3.31%, Mn – 853.61 and 728.5 mg kg?1, Zn – 105.21 and 83.92 mg kg?1 and TP – 1445.63 and 1069.8 mg kg?1. The heavy metal content of the sediments follow the order: Asian sea bass>white shrimp>tilapia. Cadmium and Cu in Asian seabass and white shrimp farm sediments would pose a major potential risk. Further, the sediment is highly enriched by Fe, P, Mn and Co.  相似文献   

19.
Juvenile Arctic char, Salvelinus alpinus (L.), were fed two levels of polyunsaturated fatty acids (PUFA) (5.5 or 2.5% of diet (37 or 16% of lipid respectively)), -tocopheryl acetate (70 or 300 mg kg–1 diet) and the antioxidant spermine (0 or 250 mg kg–1 diet) in a 3×2 factorial design and analysed for tissue fatty acid composition and indices of oxidative stress. The effect of temperature was evaluated by first maintaining the fish at 12 °C for 70 days and then 0.6 °C for 71 days. Liver and muscle fatty acid compositions were significantly influenced by the fatty acid compositions of the feed, although extensive modification of some fatty acids took place prior to deposition in the tissues. Maintaining char at low temperature increased liver PUFA content particularly in fish fed the low PUFA diets while no major changes were seen in muscle. Tissue - tocopherol deposition was mainly influenced by dietary - tocopheryl acetate. Dietary spermine had no influence on tissue levels of spermine. Dietary manipulation had no major influence on haematology and blood chemistry. High dietary PUFA increased the content of thiobarbituric acid reactive substances (TBARS) in both liver and muscle. Neither -tocopheryl acetate nor spermine influenced tissue TBARS content. Lowering the environmental temperature influenced several parameters including haematology, blood chemistry and muscle spermine content, but none were related to diet. It is concluded that Arctic char is tolerant to a wide range of dietary content of PUFA (16 to 37% of lipid) and - tocopherol (70 to 300 mg kg–1), and that spermine offers no further protection against oxidative stress. It is suggested that toxic levels of PUFA is related to the amount in dietary lipid where more than 50% of lipid may be harmful to the fish.  相似文献   

20.
To investigate the effects of dietary pyridoxine (PN) on antioxidant status of fish in serum, intestine and trunk kidney, 1050 juvenile Jian carp (11.7 ± 0.1 g) were used for the experiment. The carp were divided into seven groups and fed diets containing graded levels of PN (0.20, 1.71, 3.23, 4.96, 6.32, 8.58 and 12.39 mg kg?1 of diet) for 80 days. Results of the study showed that content of malondialdehyde in serum, intestine and kidney tissues was the highest when fed the diet containing 1.71 mg PN kg?1 diet (P < 0.05). Meanwhile, the protein carbonyl content of intestine and kidney tissue showed a downward trend to a point (P < 0.05). Conversely, activities of superoxide dismutase, catalase, glutathione peroxidase (GSH‐Px), glutathione S‐transferase, glutathione reductase and glutathione (GSH) content in serum, intestine and kidney tissue were generally higher in PN‐supplemented diets than unsupplemented diet (P < 0.05). The present results indicated that the PN decreased lipid peroxidation and protein oxidation in fish, and partly because of its improved antioxidant enzymes activities and levels of GSH.  相似文献   

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